Line circuit breaker and magnet yoke for a line circuit breaker

Abstract

In line circuit breakers with a combined overcurrent/short-circuit current tripping device, tripping should take place in a well defined manner in the case of an overcurrent and in the case of a short-circuit current. For this purpose, gaps (A, B) need to be set precisely. If the housing is made from a cost-effective housing material such as thermosetting plastic it is subject to shrinkage. As a result, the mentioned gaps may change. An armature ( 24 ) is mounted in such a way that it changes its rest rotary position in the event of shrinkage of the housing. A magnet yoke ( 28 ) as part of the overcurrent/short-circuit current tripping device is mounted and shaped in such a way that the rotation is compensated for precisely, so that the mentioned gaps do not change despite the shrinkage.

1. A magnet yoke for a line circuit breaker, on which a conductive bimetallic element is arranged and which comprises a base body, which is designed to guide magnet field lines emerging from the bimetallic element during the current flow to a field line outlet plate, by the surface normal of which a first direction is defined and with mounting sections being defined on two opposite sides of the magnet yoke, with which the magnet yoke can be supported in a housing and which allows the introduction of forces from the housing into the magnet yoke in a second and third direction at a predetermined angle to the first direction in each instance, wherein
 a deformable element is arranged between one of the two mounting sections and the base body, which element deforms with the introduction of forces acting in the second and third direction and as a result allows a movement of the field line outlet plate in a direction, which essentially corresponds to the first direction. 
 
     
     
       2. The magnet yoke according to  claim 1 ,
 wherein 
 the deformable element is rod-shaped and has two points with a reduced cross-section which are used as desired flexion points. 
 
     
     
       3. The magnet yoke according to  claim 2 ,
 wherein 
 the rod-shaped deformable element extends linearly at an angle of 35° to 55° in respect of the first direction on the one hand and in respect of the second direction on the other hand from a mounting section to the base body. 
 
     
     
       4. The magnet yoke according to  claim 1 ,
 wherein 
 one of the two mounting sections is embodied as a T-shaped foot, which allows the engagement of a screw on a limb for defining a position of the foot and thus of the magnet yoke and allows an abutment on another limb in order to hold the foot in the case of different positions of the screw. 
 
     
     
       5. The magnet yoke to  claim 1 ,
 wherein the magnet yoke 
 it is embodied as a stamped bending part. 
 
     
     
       6. A line circuit breaker, comprising a housing, in which a switching device with a switch that can be switched on and off and a combined overcurrent short circuit current tripping device are arranged, with the overcurrent short circuit current tripping device on the one hand including an armature and on the other hand including a magnet yoke, on which a bimetallic element is fastened, by means of which current flows when the switch is switched on, with a field line outlet plate being arranged on the magnet yoke, on which field line outlet plate magnetic field lines emerging from the bimetallic element during current flow and guided by the magnet yoke appear, with the bimetallic element being arranged on one side of the armature in order to press against the armature during overcurrent and also with the field line outlet plate being arranged on an opposite side of the armature in order to magnetically attract the armature during short circuit current so that both during overcurrent and during short circuit current the armature is rotated out of a rotational position at rest in the same predetermined direction, with the rotation potentially causing the switch to be switched off,
 wherein 
 the housing is subject to shrinkage and the armature is mounted such that during the housing shrinkage, its rotational position at rest changes and the magnet yoke is mounted such that it likewise receives forces during a housing shrinkage and that the magnet yoke is molded such that the received forces effect a change in the position of the bimetallic element and the field line outlet plate such that the change in the rotational position at rest of the armature is counteracted and this is balanced out. 
 
     
     
       7. The line circuit breaker according to  claim 6 ,
 wherein 
 the magnet yoke is a magnet yoke on which the conductive bimetallic element is arranged and which comprises a base body, which is designed to guide magnet field lines emerging from the bimetallic element during the current flow to a field line outlet plate, by the surface normal of which a first direction is defined and with mounting sections being defined on two opposite sides of the magnet yoke, with which the magnet yoke can be supported in a housing and which allows the introduction of forces from the housing into the magnet yoke in a second and third direction at a predetermined angle to the first direction in each instance, wherein a deformable element is arranged between one of the two mounting sections and the base body, which element deforms with the introduction of forces acting in the second and third direction and as a result allows a movement of the field line outlet plate in a direction, which essentially corresponds to the first direction. 
 
     
     
       8. The line circuit breaker according to  claim 7 ,
 wherein the deformable element is rod-shaped and has two points with a reduced cross-section which are used as desired flexion points. 
 
     
     
       9. The line circuit breaker according to  claim 8 ,
 wherein the rod-shaped deformable element extends linearly at an angle of 35° to 55° in respect of the first direction on the one hand and in respect of the second direction on the other hand from a mounting section to the base body. 
 
     
     
       10. The line circuit breaker according to  claim 7 ,
 wherein one of the two mounting sections is embodied as a T-shaped foot, which allows the engagement of a screw on a limb for defining a position of the foot and thus of the magnet yoke and allows an abutment on another limb in order to hold the foot in the case of different positions of the screw. 
 
     
     
       11. The line circuit breaker according to  claim 7 ,
 wherein the magnet yoke is embodied as a stamped bending part.